Method and apparatus for delivering precursors to a plurality of epitaxial reactor sites

Abstract

A method and apparatus for the bulk delivery of a precursor, such as an organometallic compound, from a bulk container, such as a bubbler ( 1 ) to a plurality of reactor sites ( 12, 14, 16, 18, 20 ) wherein a carrier gas ( 2 ) is introduced into the container ( 1 ) of the precursor to pick up the precursor to form a gaseous mixture. The gaseous mixture is then selectively distributed to one or more of a plurality of reactor sites ( 12, 14, 16, 18, 20 ). The gaseous mixture may be stored in a reservoir ( 9 ) and be drawn by means of a pressure differential or under vacuum to each of the reactor sites, when required.

What is claimed is:  
     
       1. A method for delivering an organometallic compound to a plurality of reactor sites, the method comprising the step of introducing a carrier gas into a container of the organometallic compound, picking up the compound in the gas to form a gaseous mixture, transporting the gaseous mixture to a reservoir and selectively distributing the gaseous mixture to one or more of a plurality of reactor sites, the method excluding the step of condensing the gaseous mixture. 
     
     
       2. A method as claimed in  claim 1 , wherein the rate of flow of the carrier gas and the carrier gas/organometallic mixture is controllable. 
     
     
       3. A method as claimed in  claim 1 , further comprising introducing a second source of carrier gas into the gaseous mixture after pick up of the organometallic compound. 
     
     
       4. A method as claimed in  claim 3 , wherein the addition of the second source of carrier gas is monitored top maintain the vapour concentration below saturation. 
     
     
       5. A method as claimed in  claim 1 , further comprising the step of heating the gaseous mixture. 
     
     
       6. A method as claimed in  claim 1 , wherein the gaseous mixture is drawn under vacuum or by means of pressure differential from the reservoir to each of the reactor sites. 
     
     
       7. A method as claimed in  claim 1 , wherein the pick up of organometallic compound in the carrier gas is kept constant. 
     
     
       8. A method of claimed in  claim 7 , wherein a constant pick up is achieved over flow rates ranging from 0 to 10 liters per minute. 
     
     
       9. A method as claimed in  claim 1 , wherein the carrier gas is hydrogen. 
     
     
       10. An apparatus adapted for delivering an organometallic compound to a plurality of reactor sites, the apparatus comprising an inlet adapted for introducing a carrier gas into a container of the organometallic compound, a reservoir for storage of the gaseous mixture of the compound and the carrier gas and an outlet for selectively distributing the gaseous mixture to one or more of a plurality of reactor sites, the apparatus excluding a condensor for condensation of the gaseous mixture. 
     
     
       11. An apparatus as claimed in  claim 10 , wherein one or more mass flow controllers are provided to control the rate of flow of the carrier gas and the carrier gaseous mixture through the apparatus. 
     
     
       12. An apparatus as claimed in  claim 11 , wherein a first mass controller is positioned to control the rate of flow of carrier gas into the container. 
     
     
       13. An apparatus as claimed in  claim 10 , further comprising means for introduction of a second source of carrier gas into the gaseous mixture after pick up of the organometallic compound. 
     
     
       14. An apparatus as claimed in  claim 13 , wherein a second mass flow controller is provided to monitor the addition of the second source of carrier gas. 
     
     
       15. An apparatus as claimed in  claim 13 , wherein the second mass flow controller is linked to the first mass flow controller. 
     
     
       16. An apparatus as claimed in  claim 10 , wherein the reservoir is provided with a pressure controller. 
     
     
       17. An apparatus as claimed in  claim 10 , wherein means is provided to allow the gaseous mixture to be drawn under vacuum or by means of a pressure differential from the reservoir to each of the reactor sites. 
     
     
       18. An apparatus as claimed in  claim 10 , wherein each reactor site is provided with its own mass flow controller to determine the rate of entry of the gaseous mixture into the reactor. 
     
     
       19. An apparatus as claimed in  claim 10 , wherein the container of organometallic compound is a bubbler, the carrier gas being introduced into the bubbler by means of a dip pipe. 
     
     
       20. An apparatus as claimed in  claim 19 , wherein the bubbler is surrounded by a temperature controlled oil bath. 
     
     
       21. An apparatus as claimed in  claim 19 , wherein the bubbler is provided with means for monitoring the level or organometallic compound therein.